18728441 has 4 divisors (see below), whose sum is σ = 19830132. Its totient is φ = 17626752.

The previous prime is 18728399. The next prime is 18728447. The reversal of 18728441 is 14482781.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7812025 + 10916416 = 2795^2 + 3304^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18728441 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (18728447) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 550820 + ... + 550853.

It is an arithmetic number, because the mean of its divisors is an integer number (4957533).

Almost surely, 2^18728441 is an apocalyptic number.

It is an amenable number.

18728441 is a deficient number, since it is larger than the sum of its proper divisors (1101691).

18728441 is a wasteful number, since it uses less digits than its factorization.

18728441 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1101690.

The product of its digits is 14336, while the sum is 35.

The square root of 18728441 is about 4327.6368840280. The cubic root of 18728441 is about 265.5627816628.

The spelling of 18728441 in words is "eighteen million, seven hundred twenty-eight thousand, four hundred forty-one".